**Figure 3.** Total cross section (TCS) for single ionization in collisions of H^{+} on Ar targets as a function of the collision energy. Theory: ⋅⋅⋅⋅⋅⋅, *post*-CDW-EIS calculations with asymptotic charges; — —, *post*-CDW-EIS calculations with effective charges; −− − − − −, *complete post*-CDW-EIS calculations with effective charges; − − − −, *prior*-CDW-EIS calculations with effective charges.

**Abstract**

A complete formulation of the *post*-version of the continuum distorted wave-eikonal initial state (CDW-EIS) model is used to investigate single ionization of multishell atoms by fast bare proton beams. The influence of the non-ionized electrons on the dynamic evolution is studied for each of the different shells of the targets. Its inclusion was made by means of the parametric Green–Sellin–Zachor potential. In this way, it is shown that discrepancies between the *prior-* and *post*-versions of the CDW-EIS model are avoided for any *nl* states of the systems studied here. The present analysis is supported by comparisons with existing experimental electron emission spectra.